mobile view

[dozen2]

I am using a 3rd party theme  and 3rd shirt design application- module.  could someone  please tell me what I need do  fix  mobile view  of this module .. the  shirt designer  module does not display well on phones. this is the link

https://printcreek.com/en/module/tshirtecommerce/designer?product_id=699&parent_id=37

Btw, the site displays well on both desktop and mobile,   when I use the default theme.. 

 I am not coder, so please by gentle with your instruction.. thanks a ton in advance